When Indiana last week enacted a law that, its critics say, could make it easier to discriminate against gays, there was a collective freakout by organizations that wear their progressive political credentials on their sleeves. The consumer outfit Angie’s List canceled a $40 million expansion of its corporate headquarters in Indianapolis, and the NCAA issued barely veiled threats to shut down its national offices in the city. Gen Con, a huge gaming convention, said it might take its business elsewhere.

None of them said where they might go. But I imagine it will have to be Canada. Because, guess what: Indiana’s Religious Freedom Restoration Act is already federal law. Indiana’s law is a virtual clone of one passed nearly unanimously by the U.S. Congress in 1993 and signed without complaint by Bill Clinton.

What’s more, 19 other states have already passed their own versions of the RFRA. That became necessary after the U.S. Supreme Court upheld the law in federal jurisdictions but said Washington could not enforce it against states.

So why is it that that you’ve probably never heard of the RFRA before even though you’ve been living under it, in one form or another, for more than two decades? Probably because it’s not the savage instrument of gay-bashing that it’s being made out to be. It’s a law intended to prevent the rights of religious minorities being unnecessarily trampled by government.

The RFRA has its roots in a 1963 ruling by Earl Warren’s liberal Supreme Court in the case Sherbert v. Verner. Adell Sherbert was a member of the Seventh-day Adventist Church who quit her job at a textile mill when it ordered her to work on Saturday, her religion’s Sabbath.

South Carolina denied her request for unemployment benefits, but the Supreme Court said its policy violated Sherbert’s right to practice her religion without any compelling reason to do so. For most of the next three decades, the so-called Sherbert Test — does this governmental action needlessly burden the practice of religion? — governed the legal battleground between state and church.

But in 1990, the more conservative Supreme Court of William Rehnquist essentially did away with the Sherbert Test. In the case Employment Division v. Smith, the court upheld Oregon’s refusal to pay unemployment benefits for two men fired from their drug-rehab counseling jobs after they were caught using peyote as a rite in the Native American Church. The law was targeted on everybody, the court ruled, not just church members, so tough beans.

It was popular outrage over the Smith decision that led to passage of the federal RFRA three years later, reestablishing the Sherbert test for court cases involving religious liberty. And while the new law had support across the political spectrum, it was liberal groups like the ACLU and the American Jewish Congress that really muscled it through.

The bill was sponsored by progressive poster boy Charles Schumer, then a New York congressman, now a senator, though that seems to have slipped his mind.

When the Indiana law took effect last week, Schumer immediately tweeted that the NCAA should move this year’s Final Four basketball games to New York, where there are “plenty of great venues that don’t discriminate.”

Why liberals, who used to think the RFRA was a great piece of civil-liberties legislation, now regard it as a jihadist attack on gays is a profound mystery. If it’s been a factor in any major case involving discrimination against gays, I haven’t been able to find it. Mostly it’s invoked for stuff like whether Amish buggies in Minnesota must have fluorescent lights or if Texas preservationists can block renovations on a historic church.

Sometimes the religionists win (in Minnesota) and sometimes they lose (in Texas), because the RFRA doesn’t establish any absolute rights for religion. It simply calls for courts to use a balancing test in evaluating whether laws crimp the practice of religion. There’s not a single word in the law about gays or discrimination. But don’t take my word for it.

Just ask President Obama, who as a state legislator voted in favor of an RFRA in Illinois in 1998.